*Overview*
These bushings are designed to be compatible with KPTexans Brass Cartridge Trimmer, which I'm a big fan of. These bushings reference the shoulder of a resized brass cartridge case, and allow cartridge cases to be trimmed to a length determined by the end user.
*Bushing Design*
The basic bushing design is identical to KPTexan's, as it was derived from his .dwg.
For each cartridge/bushing, KPTexans basic method of design was used for consistency/compatibility. This basic method is as follows:
- Within the bushing, draw the cartridge neck, shoulder, and case wall using standard CIP drawing dimensions in metric.
- Adjust the neck length within in the bushing such that 2.0mm of the neck would protrude from the bushing when trimmed to CIP length
- Add 0.15mm to the neck and shoulder radius
- Add a 2.0mm radius to the intersection of the neck and shoulder
- Add a 0.6mm chamfer at the base of the bushing
- Revolve the drawing within the bushing to create the cavity
*Additional Parts*
These bushings are held in position just like KPTexan's, via a light interference and a SAE Size 016 O-Ring per bushing
*Cartridges Currently Available*
The bushings I have made thus far:
- 7.62x45mm Czech
- 7x57mm Mauser
- 8x57mm Mauser
- 7.7x58mm Japanese
- 6.5x51Sr Japanese
- 7.5x54 MAS
*Alibis by Cartridge*
- 7.62x45mm Czech - No issues
- 7x57mm Mauser - Not yet tested
- 8x57mm Mauser - Not yet tested
- 7.7x58mm Japanese - Maybe a little loose at the base by 2-5 thou, no noted issues with results.
- 6.5x51Sr Japanese - No issues
- 7.5x54 MAS - Not yet tested
*Printing*
Accomplished with Bambu Labs basic PLA in various colors.
220C Hotend Temp
55C Bed
.2mm layer height
3-4 wall loops
3-5 Bottom and Top layers as desired
30-40% rectilinear infill
No support required
Printables Tags: brass; reloading; trimmer